Velocity (v) versus displacement (x) plot of a body moving along a straight line is as shown in the graph. The corresponding plot of acceleration (a) as a function of displacement (x) is
Acceleration
Now for 0 ≤ x ≤ 100, v = kx
dv/dx = k
a = k(kx) = k2x
Again for 100 ≤ x ≤ 200, dv/dx = -k and v = c - kx
a = (-k)(c - kx) = k2x - kc.
Therefore option (4) is correct.